Sperm cryopreservation of freshwater fish bocachico ( Prochilodus magdalenae ) in DMSO and glucose and its effects on fertilization and hatching efficiency
Martinez, J GTarazona-Morales, A MPardo-Carrasco, S C
Internal cryoprotectants (dimethyl sulfoxide - DMSO), as well as exter nal ones (glucose) have been of great importance for sperm cryopreservation in freshwater fish. The aim of this study was to evaluate both the fertilization and hatching rates of eggs fertilized with bocachico ( Prochilodus magdalenae ) spermatozoa cryoprese rved in different combinations of DMSO and glucose. Nine treatments were evaluated by a combination of three concentrations of DMSO: 5% (701 mM), 10% (1402 mM), 15% (v /v ; 2103 mM) and three concentr ations of glucose: 5.5% (305 mM), 6% (333 mM), 6.5% (w /v ; 361 mM) . Semen from males obtained by abdominal stripping 6 h after hormonal induction with carp pituitary extract was submitted to each treatment. The semen was frozen in 0.5 m l straws in a nitrogen vapor dry shipper for 30 m in and then in liquid nitrogen ( - 1 96°C). Five days later they were placed in water with a temperature of 60 °C for 8 sec and analyzed. A high total motility (71 .0 ± 7.0%) was observed when DMSO concentration was 10% and glucose was 6%, and a high linearity displacement (62.8 ± 6. 3 %) was observed when DMSO concentration was 5% and glucose was 5.5%. In conclusion, we found that for the purposes of cryopreservation of bocachico spermatozoa, the combination s of 10% DMSO + 5.5 or 6% glucose and 5% DMSO + 5.5 or 6% glucose produced the best re sults in terms of fertilization and hatching rates. This becomes the first report to successfully demonstrate the fertilizing capacity and larvae obtaining capabilities of cryopreserved bocachico semen.(AU)
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